British A-Class weapon

European Champion Chris Field tells us of his campaign and his Vision A-Cat

Wednesday March 13th 2013, Author: James Boyd, Location: United Kingdom

Thanks to the sterling efforts of the national class association, A-Class catamaran racing in the UK – sadly dormant for many years – is now getting back on its feet.

The demographic of the A-Class is an interesting one, a combination of ‘more experienced’ catamaran sailors who can afford the reasonably costly hardware (a new boat is in the order of 15,000 Euros from the manufacturer) and high profile Olympic and professional sailors, looking to gain some two hulled experience en route to the America’s Cup. Finn sailor Giles Scott acquired a Bimare A-Class catamaran last year and having been with Team Korea has since been signed up by Luna Rossa. 470 silver medallist turned 49er sailor Stuart Bithell and Paul Goodison are also A-Cat owners.

Aside from the ‘stars’, numbers are steadily growing among the rank and file and at last year’s Nationals there were 13 boats, with Phil Neal, one of the movers and shakers at the hosts, Rutland Sailing Club, crowned UK champion.

However the standout A-Class sailor in the UK is unquestionably Chris Field, the current European champion, who finished ahead of more than 100 other A-Cats on Lake Garda last summer.

Field, 31, back in the day raced Tornados with his brother, and while he temporarily shelved his sailing while he attended college, on his return in 2005 has since mostly gone down the singlehanded cat racing route. As he recalls: “I just wanted a boat that was going to be easy to sail on my own. I wasn’t going to take it very seriously. I was going to do the UK circuit and that was it. But within three months I found myself at the World Championships! I came 16th, so then I thought I’d take it more seriously.”

Today Field lives in Minnis Bay on the north Kent coast, just five minutes from his sailing club.

Field campaigned a DNA for a while and this remains the most prevalent boat in the class. Last year Mischa Heemskerk (above right with Chris Field and National Champion Phil Neal, left) won the A-Class Worlds in Pensacola, Florida aboard one and its Dutch manufacturer Advanced Racing Catamarans has churned out some 150 examples to date – a large number of the traditionally exotic catamaran. At the Europeans last year Field claimed the title but was beaten by an Australian, Andrew Landenberger, sailing a Swiss-designed Scheurer design (who in turn have a new model coming out – the D3 is being built by famous IMOCA 60 builder, CDK Composites in France).

However in 2010 Field moved across to sail another Dutch-built boat called the Vision and this was on display on the A-Class stand at the RYA Dinghy Show weekend before last. Field has helped in the development of the Vision. The boat went into production at the beginning of last year, built by Catamaran Parts (who are also behind the Raptor F16) to a design by A-Class legend and mast designer/builder Piet Saarberg, whose family runs Catamaran Parts. Around 10 Visions have been launched to date.

Design of the Vision bucks the trend in recent catamaran design - rather than going for reverse Dreadnought-style bows, hers are more upright. Interestingly though, Field makes the point that despite this, the Vision’s bows are still ‘wave piercing’. “It was a conscious design decision from the manufacturer – it is the distribution of the volume of the front that makes it wave piercing, not the angle fore and aft. In fact it is one of the best boats for getting through the waves, it just happens to be straight at the front rather than being swept back. But it obviously helps to differentiate it as well...”

The Vision hulls have slightly more rocker and slightly less freeboard than the baseline DNA A-Cat, but the amount of volume in the hulls is otherwise similar.

As is now more or less standard- for A-Class catamarans, C-shaped daggerboards are fitted on the Vision.

According to Colin Bannister, Chairman of the British A-Class Catamaran Association, there has been considerable experimentation with daggerboards over recent years. For example the makers of the new Paradox A-Cat (Dario Valenza of Carbonic Boats down in Australia, also a one time AC34 challenger) have allegedly trialled five different designs of boards, including an S-shaped boards like the first Kiwi AC72 (and Alinghi 5).

However most modern A-Cats have curved C-shaped boards, although between these there are differences between the boards' radius of curvature (more radius equals more vertical lift).

Significantly boards must fit within A-Class rules that prohibits their top or bottom from extending outboard of the 7ft 6in (2.3m) maximum beam permitted, but also not within 0.75m of the boat’s centreline (ie the furthest inboard parts of each board must be 1.5m apart). In addition to this the boards must be inserted within the maximum permitted beam of the boat.

As daggerboards have begun developing more vertical lift, so this has affected their fore and aft position in the boat and on the Vision they are indeed well aft. “The trend has been to move them further and further back over the years,” confirms Field. “This is the optimum for this design, beneath the centre of effort for the rig, so the boat is incredibly well balanced. It doesn’t quite sail itself, but not far off.”

Whereas once upon a time catamaran daggerboards/centreboards were only to prevent leeway, thanks to the curved foils and their lift characteristics, so the fore and aft positioning of crew weight has become more critical. As Field observes: “Basically it is about keeping the flow going over the boards all of the time. You see lots of pics of the A-Class jumping out of the water and the crew being thrown off the back – that is the crew not moving their body weight into the correct position. You have to keep the foils trimmed to the water at the correct angle – then you get no issues.”

The vertical lift being generated by the leeward board is very noticeable, says Field: “Before the curved daggerboards, a lot of people would sit on the side of the boat. Now you trapeze and that is because the boat is being lifted out of the water, there is less drag, it makes the boat feel lighter, etc. It is coming out of the water slowly but surely, but at the moment the rules limit that.” Ie: the rule preventing foils from encroaching within 0.75m of the centreline nor outboard of the maximum permitted beam, effectively limiting the size of the vertical planing surface.

Another trend in the A-Class, as exemplified by the Vision is the use of fixed mini winglets on each rudder, designed to reduce pitching. Winglets such as this is not new on A-Cats - sailor, sailmaker and International Class President, Andrew Landenberger has been using them for years for example - however it is only very recently that they have caught on. “This year everyone is moving towards the winglets on the rudders,” confirms UK Class Chairman Colin Bannister. “They give more stability particularly downwind. If you are bow down then they will dig in and pull the back end down and vica-versa. They just keep the boat flat.”

Field observes that while there are a great many different A-Class designs and manufacturers, all the latest boats go much the same speed (as would be expected with boats built to a 60 year old box rule) only there are minor differences in how they get there. Field says of the difference sailing the Vision to the DNA: “The DNA is a very forgiving boat to sail whereas this [the Vision] you have to be more precise sailing it, and ultimately I think it is just a fraction quicker.”

Obviously vital to the A-Class is its unarig (like C-Class cats, As are hamstrung by having a fixed maximum sail area and so can’t use kites increasing their sail area downwind). The Vision features a robust-looking Saarberg spar while Field works with Mickey Todd at HammerSails in Spain for his sail. “The rig is still the most important thing on the boat,” observes Field.

This year Field intends to compete in all the UK events starting with the Datchet Fast Cat Open this weekend. He will also head for Barcelona at the end of June to defend his European title, and to Lake Constance mid-May where the A-Class is holding a combined German, Austrian and Swiss national championship mid-May at Bodensee. If the Worlds and Europeans in the A-Class are typically restricted to 100 boats, then this open event has the potential to be far larger...

Then there’s the French Nationals, another event where Field intends to go this year to defend his title.


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